Single-station shellmolding machine



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United States Patent 2,864,135 SINGLE-STATION SHELLMOLDING MACHINE Paul Klamp, Detroit, Mich, assignor to Mechanical Handling Systems, Inc., Detroit, Mich, a corporation of Michigan Application May 5, 1955, Serial No. 506,168 4 Claims. (Cl. 2220) This invention relates to improvements in the construction of a shellmolding machine of the single station type that is a machine having but one mold forming station which is provided with a pattern carrier and a sandbox for holding the mold forming composition.

The invention particularly pertains to improvements in the relationship between the oven and the components of the mold forming station and the general object of these improvements is to obtain a more complete and uniform distribution of heat over the surfaces of the mold being cured.

I am familiar with several machines of this type which have previously been developed. In all of these a curing oven is mounted on the framework of the machine and is moved over the top of the mold for the curing phase. The structure of the mold forming station in these prior machines has been such as to make it impossible to provide an oven which completely surrounds the pattern andv mold to be cured thereon. Consequently in these prior machines heat distribution is poor, heat losses are high and frequently auxiliary heating means have to be provided in an effort to cure these shortcomings. Such auixiliary heating means usually take the form of electrical heating elements incorporated in the pattern plate.

In the present invention the mold forming station includes all the conventional components, namely, a pattern carrier, a sandbox, a stripper plate forming part of the pattern carrier structure and a knockout plate. The pattern carrier is supported by structure located-laterally of that portion of the carrier which receives the pattern. The knockout member occupies a normal position well below the normal level of the pattern carrier. An oven is movably supported on the framework of the machine. This oven is equipped with top, bottom and side walls. The end of the oven closest the mold forming station is partially open while the other end is fully closed. The end opening is continued in a slot which extends along that side of the oven closest to the supporting structure of the pattern carrier. 7

As a result the oven can be moved to a curing position and in that position it completely surrounds the pattern. Preferably the oven is equipped with two heating elements or burners. One of these is located above and to one side of the position occupied by a pattern being cured. The other burner is located below and to the other side of the pattern. These burners are used in conjunction with heat deflecting means which serve to produce a circulation of hot gases over all surfaces of the pattern.

The stripper plate is suspended from the pattern carrier at some distance beneath the lower surface of a pattern supported thereby, and the lower of the two oven heating elements, and deflectors associated therewith, are positioned at a level intermediate the stripper plate and pattern. Thus hot gases pass between the stripper plate and pattern, and the stripper plate does not shield any portion of the pattern surface from the heat.

Preferably a stationary closure member is incorporated which acts to substantially seal the open end of the oven when the oven is moved to curing position.

Other features of the invention will appear in connection with the following description of the representative embodiment of the invention shown in the accompanying drawings which comprise:

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Fig. 1, a plan view of the machine;

Fig. 2, a front elevation thereof;

Figure 3, an end elevation taken from the left-hand side of Fig. 2 with a portion of the framework structure removed for the sake of clarity;

Fig. 4, a schematic view illustrating the movements of the parts in a mold forming cycle;

Fig. 5, a schematic view illustrating control elements employed to govern the cycling of the machine;

Fig. 6, an elevation on a reduced scale showing the open end of the oven; and

Fig. 7, a sectional elevation along the line 7--7 of Fig. 6.

Referring. to Figs. 1, 2 and 3, the main components of the mold forming station include a pattern carrier 10 and a sandbox 11 which are supported for movement about a pivotal axis provided by the shaft 12. Pattern carrier and sandbox as well as their cycle of movement are fully described in copending application Serial No. 299,606, filed July 18, 1952, and entitled Turntable Type Machines for Forming Shell Molds, now Patent 2,762,092, issued September 11, 1956. Other details of the sandbox construction are disclosed in copending application Serial No. 440,604, filed July 1, 1954, and entitled Sand box Construction for Shellmolding Machines.

In the present construction shaft 12, to which supporting arms 13 of the pattern carrier are keyed is driven from motor 14 (Fig. 1) through gear box 15 which drives shaft 16 (Fig. 2). A gear 17 equipped with a pair of drive pins 18 and 19 is mounted on the end of shaft 16 at the left side of the machine as the parts are viewed in Fig. 2. The gear 17 and pins 18 and 19 drive shaft 12 through the combination of a gear sector 20 and cams 21, 22 and 23 secured to the gear sector.

Movement of the pattern carrier 10 and sandbox 11 is required in the following sequence from the normal position of these parts shown in Fig. 3 during a mold forming cycle.

A. Pattern carrier 10 is moved counterclockwise into contact with the sandbox 11 and is latched thereto.

B. Pattern carrier and sandbox are moved clockwise to the position indicated by the reference 25, Fig. 4.

C. Pattern carrier and sandbox are returned to the normal position of the latter and unlatched.

D. Pattern carrier is returned to its normal position.

Cams 21 to 23 act to impart uniform acceleration and deceleration to the pattern carrier and sandbox during the foregoing movements. Cam 21 performs this function on movements A and C, cam 22 on movement D, and cam 23 on movement B.

A stripper plate 30 on which stripper pins (not shown) are mounted, is suspended from the pattern carrier on guide pins 31. A knockout plate 32 is mounted on the rod of a hydraulic cylinder assembly 33 which is mounted in the base structure 34 of the machine. Particulars of the construction and operation of stripper plate and knockout plate are fully described in my copending application Serial No. 505,291, entitled Shellmold Stripping Mechanism.

A curing oven 40 is mounted on four wheels 41 which travel on rails 42 supported by the machine base. These rails 42 extend through the curing station as shown in Figs. 1 and 2. The oven structure includes a top wall 44, a bottom wall 45, an outer side wall 46 and an inner side wall, adjacent the pattern carrier supporting shaft 12, made up of two panels 47 and 48 whose adjacent ends are separated by a slot 49. The end 52 of the oven closest to the mold forming station is partially open as can be seen in Figs. 3 and 6. The opposite end 54 is fully closed and mounted in this end 54 are a pair of burners 55 and 56. Figs. 3 and 6 show the relative transverse location of these burners, burner 55 being located above and to I one side of a pattern plate 58 supported by the carrier 10. Burner 56 is below and to the other side of the pattern and is positioned at a level intermediate the lower pattern surface and thenstripper-plate 30. A heat deflector is preferably employed in conjunction with-each burner. Each defiectorhas a-seriesof-progressive curved baffles 60-, 61 and- 62 (Fig. 1), mounted on a supporting plate 63. These deflectors extend into the -path of hotgasesfrom each burnerand'deflectthese gases uniformly from one side of the oven to theother,-sett-ing up a path of heat circulation: above and below'the pattern surface 58 as indicated by the arrows and65 in Figs. 3 and 6.

Overt 40 is moved fromthe normal position shown in Figs. 1 and 2 to a curing position where it surrounds the pattern carrier by amotor 68 driving acrank 69 through a gear box 70. A follower 71 on the end of the crank 69 engages in guides 72 on the bottom :of the oven. A paneln66 is mounted on the supporting frame 67 at the left of the machine and is dimensioned to cover the opening of .the end 52 of theoven when the oven is moved to curing. position- It will thus be seen that when the oven is in curing position the pattern 58 is completely enclosed, except for the slot 49'through which the arms 13 of the pattern carrier extend. Heat is circulated over all surfaces of the pattern with a uniformity that can be regulated by the shape, number and position ofthe baffles of the heat deflectors.

Operation of the machineis on an automatic cycle governed by conventional control elements and circuits. Thesehave not been-shown in detail as it is felt that those skilled in the art canreadily provide the necessary circuitry to accomplishlthe desired'operation. The major controlelements and theirrelation to the various components to the machine are disclosed (particularly in Figs. 4 and and the cycle-of the machine will be briefly outlined. Motors 14 and 68 are both .of the reversible type. When the machine is started motor 68 is energized to move the oven. 40 to the left as the parts are shown in Figs. 1 and 2 to preheat-the pattern. This operation is interlocked with limit switch LS2, indicating the normal position of the platen carrier 10, and with limit switch LS1, indicating. the normal position of the knockout plate 32. Oven movement is controlled by contact between a block 80; adjustably mounted on the oven framework and .limit switch LS3. LS3 also actuates a timer which governs the extent of the preheating phase. After this timer times out,.motor 68 is energized to move the oven 40 to the right, back to its normal position governed by contact between a second block 82 adjustably mounted on the oven framework and LS4. LS4 also actuates motor 14 to drive the shaft 12 counterclockwise as the parts are viewed in Fig. 3 moving thepattern carrier -in contact with the sandbox 11. Such contact is accompanied byactuation of LS5 which stops motor 14 and operates a latching cylinder 74 which controls the position of a latch. assembly 75 to secure the pattern carrier.10- to the sandbox 11. When latch assembly 75 has closed, LS6 is contacted and motor 14 is reversed to move thepattern carrier andsandbox to the emersion position indicated by the line 25 in Fig. 4, where LS7 is contacted. LS7 stops motor 14 and energizes a timer (not shown) which governs the length of the emersion phase. When thisemersion timer times out, motor 14 is energized in the reverse direction to return the pattern carrier and sandbox to the normal position of the latter where LS5 is.again contacted, stopping motor 14 and unlatchingthe latch assembly 75. Unlatched position is'indicated by LSSwhich starts motor 14 to return the pattern carrier l0ato'itsxnormal position, defined by LS2. LS2 stops motor 14 a'nd ene'rgizesthe oven drivingmotor 68 to move the'oven to the left for the curing phase. This phase is initiated by LS3 whichstops the motor 68and-'-startsa=-third timer which controlsthe length of the cure.- When this thi d mer times out, motor 68 is energized to return the oven to its normal position and when this position is reached, LS4 stops motor 68 and ends the cycle.

Limit switches LS5, LS7 and LS2 governing movement of the pattern carrier and sandbox are contacted by controlcams-78, 79 and 80, respectively, which are mounted on shaft 12 and are shown in Fig. 1.

The foregoing description of the machine, its construction and operation are to be considered to be representative of the invention. The exact scope is to be found in the following claims.

I claim:

1. A shell molding machine of the type having a supporting framework, said framework being stationary, molding'station components including a pattern carrier and sand box mounted on said framework, said pattern carrier being supportedlaterally of the patternr'eceiving portion'thereof, means forrnoving said pattern carrier and sand box ina"m'ol'dingcycle,' said molding cycle including a mold forming position in'which the sand box and'pattern carrier are clamped'together for forming a shell mold anda' curing position in which the sand box and pattern carrier are separated and are on oppo= site sides of their supports on the framework, and an oven supported on" said framework forreciprocating straight line movement relative to said pattern carrier from a normal position adjacent said pattern carrier in the curing position thereof to and from a curing position in a curing cycle; characterized by said'oven including top; bottom andside' walls, a slot provided along the side wall adjacent the said pattern carrier support, said oven further'includingan open end adjacent said mold ing station andan'end'wall at the other end thereof, said open end-being located'to' one side of saidpattcrn carrier whensaid oven is in-normal position, an oven closure member fixedly mounted adjacent the other side of said pattern carrier, and means for "reciprocally moving said oven from saidnormal position to saidcuring position' to place the said oven open end adjacent said oven closure member in curing position'whereby said pattern carrier is enclosed for curing a mold supported thereon.

2. A shell molding 'machineaccording to claim 1 further characterized by a knockout member carried'by said framework for'mov'ement from a normal position below the level of the bottom'wall of said oven to a knockout position upwardly relative to said pattern'carrier through the space vacated by saidoven when'said'oven 'is returned'to its normal positionfrom its curing position.

3. A shell molding machine according to'claim '1 furthercharacterized by' the 'provision'of a pair of burners in said oven, one of said burners being mounted above and to one side of the position occupied by apattern, the other of said burners being'located below and to the other side'of suchposition, and heat deflecting means for producinga circulation of hot gases from said burners over the upper'and lower surfaces of said pattern.

4. A shell molding machine according to claim l'further characterized 'by said pattern carrierbeing provided with a stripper plate depending therefrom in'spaced relation to theunder surface of a pattern supported by said carrier, and means for supplying heat to said oven including means'for directing such'heat' into the space between said stripper plate'and' the under surface of a pattern.

References Cited in the file of this patent UNITED STATES PATENTS ,5 4,945 Coleman Dec. 8, 1925 ,962 Barnett Oct. 2, 1945 9,9 4 Valyi NOV. 24, 1953 2, 95,431 Davis Nov. 30, 1954 6 ,092 Klamp et a1. Sept. 11, 1956 FOREIGN PATENTS 97. 7 France Feb. 9. 1955 

